Question

An electric heater has a resistance of $40\Omega$ and draws a current of $4A$.

Calculate : (a) its power

(b) $p.d$. at its ends.

Answer 1

Step 1: Determine the power:

(a) Given data :

$R=40\Omega$

$I=4A$

(a) The power :

$P=I^{2}R$

$P=4\times 4\times 40$

$P=640W$

Therefore, the power of the electric heater is $640W$.

Step 2: Calculating the p.d. at its ends:

(b) The formula for calculating the$p.d$ at its ends is,

$V=\frac{P}{I}$

$=\frac{640}{4}$

$V=160V$

Therefore, the $p.d.$ at its ends is $160V$.